1Stdlib.Printf(3)                 OCaml library                Stdlib.Printf(3)
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NAME

6       Stdlib.Printf - no description
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Module

9       Module   Stdlib.Printf
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Documentation

12       Module Printf
13        : (module Stdlib__printf)
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22       val fprintf : out_channel -> ('a, out_channel, unit) format -> 'a
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25       fprintf outchan format arg1 ... argN formats the arguments arg1 to argN
26       according to the format string  format  ,  and  outputs  the  resulting
27       string on the channel outchan .
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29       The  format  string  is  a character string which contains two types of
30       objects: plain characters, which are simply copied to the output  chan‐
31       nel, and conversion specifications, each of which causes conversion and
32       printing of arguments.
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34       Conversion specifications have the following form:
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37       % [flags] [width] [.precision] type
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39       In short, a conversion specification consists in the % character,  fol‐
40       lowed  by  optional  modifiers  and  a type which is made of one or two
41       characters.
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43       The types and their meanings are:
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46       - d , i : convert an integer argument to signed decimal.
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48       - u , n , l , L , or N : convert an integer argument to unsigned  deci‐
49       mal.  Warning: n , l , L , and N are used for scanf , and should not be
50       used for printf .
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52       - x : convert an integer argument to unsigned hexadecimal, using lower‐
53       case letters.
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55       - X : convert an integer argument to unsigned hexadecimal, using upper‐
56       case letters.
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58       - o : convert an integer argument to unsigned octal.
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60       - s : insert a string argument.
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62       - S : convert  a  string  argument  to  OCaml  syntax  (double  quotes,
63       escapes).
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65       - c : insert a character argument.
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67       -  C  :  convert  a  character argument to OCaml syntax (single quotes,
68       escapes).
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70       - f : convert a floating-point argument to  decimal  notation,  in  the
71       style dddd.ddd .
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73       -  F  :  convert  a floating-point argument to OCaml syntax ( dddd.  or
74       dddd.ddd or d.ddd e+-dd ).
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76       - e or E : convert a floating-point argument to  decimal  notation,  in
77       the style d.ddd e+-dd (mantissa and exponent).
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79       -  g  or  G : convert a floating-point argument to decimal notation, in
80       style f or e , E (whichever is more compact).  Moreover,  any  trailing
81       zeros  are removed from the fractional part of the result and the deci‐
82       mal-point character is removed if there is no fractional  part  remain‐
83       ing.
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85       -  h  or H : convert a floating-point argument to hexadecimal notation,
86       in the style 0xh.hhhh e+-dd (hexadecimal mantissa, exponent in  decimal
87       and denotes a power of 2).
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89       - B : convert a boolean argument to the string true or false
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92       -  b  :  convert a boolean argument (deprecated; do not use in new pro‐
93       grams).
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95       - ld , li , lu , lx , lX , lo : convert an int32 argument to the format
96       specified by the second letter (decimal, hexadecimal, etc).
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98       -  nd  ,  ni  , nu , nx , nX , no : convert a nativeint argument to the
99       format specified by the second letter.
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101       - Ld , Li , Lu , Lx , LX , Lo : convert an int64 argument to the format
102       specified by the second letter.
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104       -  a : user-defined printer. Take two arguments and apply the first one
105       to outchan (the current output channel) and to the second argument. The
106       first  argument  must therefore have type out_channel -> 'b -> unit and
107       the second 'b .  The output produced by the function is inserted in the
108       output of fprintf at the current point.
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110       - t : same as %a , but take only one argument (with type out_channel ->
111       unit ) and apply it to outchan .
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113       - { fmt %} : convert a format string argument to its type digest.   The
114       argument must have the same type as the internal format string fmt .
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116       -  ( fmt %) : format string substitution. Take a format string argument
117       and substitute it to the internal format string fmt to print  following
118       arguments.  The argument must have the same type as the internal format
119       string fmt .
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121       - !  : take no argument and flush the output.
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123       - % : take no argument and output one % character.
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125       - @ : take no argument and output one @ character.
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127       - , : take no argument and output nothing: a no-op delimiter  for  con‐
128       version specifications.
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130       The optional flags are:
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132       - - : left-justify the output (default is right justification).
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134       - 0 : for numerical conversions, pad with zeroes instead of spaces.
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136       -  + : for signed numerical conversions, prefix number with a + sign if
137       positive.
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139       -space: for signed numerical conversions, prefix number with a space if
140       positive.
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142       - # : request an alternate formatting style for the integer types ( x ,
143       X , o , lx , lX , lo , Lx , LX , Lo , d , i , u , ld , li , lu ,  Ld  ,
144       Li , Lu , nd , ni , nu ).
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146       The  optional  width  is an integer indicating the minimal width of the
147       result. For instance, %6d prints an integer, prefixing it  with  spaces
148       to fill at least 6 characters.
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150       The  optional  precision  is a dot .  followed by an integer indicating
151       how many digits follow the decimal point in the %f , %e , and  %E  con‐
152       versions. For instance, %.4f prints a float with 4 fractional digits.
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154       The  integer  in  a  width or precision can also be specified as * , in
155       which case an extra integer argument is taken  to  specify  the  corre‐
156       sponding  width  or  precision . This integer argument precedes immedi‐
157       ately the argument to print.  For instance, %.*f prints a float with as
158       many  fractional  digits  as the value of the argument given before the
159       float.
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163       val printf : ('a, out_channel, unit) format -> 'a
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165       Same as Printf.fprintf , but output on stdout .
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169       val eprintf : ('a, out_channel, unit) format -> 'a
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171       Same as Printf.fprintf , but output on stderr .
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175       val sprintf : ('a, unit, string) format -> 'a
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177       Same as Printf.fprintf , but instead of printing on an output  channel,
178       return a string containing the result of formatting the arguments.
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182       val bprintf : Buffer.t -> ('a, Buffer.t, unit) format -> 'a
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184       Same  as Printf.fprintf , but instead of printing on an output channel,
185       append the formatted arguments to the given extensible buffer (see mod‐
186       ule Buffer ).
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190       val ifprintf : 'b -> ('a, 'b, 'c, unit) format4 -> 'a
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192       Same as Printf.fprintf , but does not print anything.  Useful to ignore
193       some material when conditionally printing.
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196       Since 3.10.0
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201       Formatted output functions with continuations.
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203       val kfprintf : (out_channel -> 'd) -> out_channel -> ('a,  out_channel,
204       unit, 'd) format4 -> 'a
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206       Same  as fprintf , but instead of returning immediately, passes the out
207       channel to its first argument at the end of printing.
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210       Since 3.09.0
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214       val ikfprintf : ('b -> 'd) -> 'b -> ('a, 'b, 'c, 'd) format4 -> 'a
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216       Same as kfprintf above, but does not print anything.  Useful to  ignore
217       some material when conditionally printing.
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220       Since 4.01.0
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224       val ksprintf : (string -> 'd) -> ('a, unit, string, 'd) format4 -> 'a
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226       Same  as  sprintf above, but instead of returning the string, passes it
227       to the first argument.
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230       Since 3.09.0
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234       val kbprintf : (Buffer.t -> 'd) -> Buffer.t -> ('a, Buffer.t, unit, 'd)
235       format4 -> 'a
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237       Same as bprintf , but instead of returning immediately, passes the buf‐
238       fer to its first argument at the end of printing.
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241       Since 3.10.0
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246       Deprecated
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248       val kprintf : (string -> 'b) -> ('a, unit, string, 'b) format4 -> 'a
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250       A deprecated synonym for ksprintf .
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256OCamldoc                          2019-07-30                  Stdlib.Printf(3)